Read in today's paper that there was a huge volcanic eruption in Iceland in the early 1700's and the dust thrown into the atmosphere completely ruined the summer here in the UK. Even worse, it disrupted the monsoon rains and caused drought and famine in Africa and Asia.

Late 18th century - Laki, 1783-5. More than "ruined the summer", there was a huge death toll from cold and hunger, and catastrophic famine in Shetland.